Variable refrigerant flow (VRF) air conditioning and related methods

ABSTRACT

Disclosed is an improved variable refrigerant flow (VRF) air conditioning (AC) unit that eliminates the need to run refrigerant lines into the spaces being cooled or heated while providing the benefits and energy savings of a VRF system. Suitably, the disclosed VRF AC system can connects multiple condensate drain pans via one pipe then uses gravity to drain condensation from the condenser coils. Further disclosed is a VRF AC system that provides the required minimum outside air as an integral part of the system. Finally, disclosed may be a VRF AC system that has an economizer to use outside air to cool inside air if the outside air temperature is lower than the inside air temperature.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part patent application of application Ser. No. 15/199,642 (filed Jun. 30, 2016) entitled “Improvements to variable refrigerant flow (VRF) air conditioning and related methods.”

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

REFERENCE TO AN APPENDIX SUBMITTED ON A COMPACT DISC AND AN INCORPORATED BY REFERENCE OF THE MATERIAL ON THE COMPACT DISC

Not applicable.

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR

Reserved for a later date, if necessary.

BACKGROUND OF THE INVENTION Field of Invention

The disclosed subject matter is in the field of systems of variable refrigerant flow (VRF) air conditioning (AC) units.

Background of the Invention

Variable refrigerant flow or VRF is a technology in the field of heating, ventilating, and air conditioning (HVAC). HVAC technology is important for the design of office buildings, where thermal comfort and acceptable air quality are regulated. In the typical case, indoor temperature regulation (the H or AC of HVAC) is accomplished by outdoor condenser coils with refrigerant that circulates via copper tubing to corresponding evaporation coils localized at various zones within the building. Ventilation (the V in HVAC) involves exchanging internal air with external air.

In typical HVAC systems for buildings with multiple zones to be cooled, refrigerant lines are run from a rooftop condensation coil to a localized evaporation coil at each zone to be cooled. A fan at each zone blows air over the evaporation coil so that heat is exchanged from the blown air and the refrigerant. During air cooling heat exchange, heat is transferred to the refrigerant as the refrigerant evaporates within the coils. Sometimes, such heat exchange causes moisture from the air to condense on the evaporation coils. After heat is exchanged between the refrigerant and the air to achieve conditioned air, the conditioned air is provided within the local zone while the refrigerant is pumped to the rooftop condensation coil. In the condensation coil outside of the building, the heat in the refrigerant is exchanged or dumped to the ambient heat sink as the refrigerant is condensed within the condensation coils. Finally, any moisture from the evaporation coils may be pumped outside of the building for drainage. Meanwhile, a ventilation fan circulates a constant flow of fresh air in and an equally constant out flow of exhaust air from the localized zones.

Several problems arise with typical temperature control in known HVAC systems. One problem is that standard HVAC systems require hundreds of feet of expensive copper tubing to circulate refrigerant between the rooftop condenser and localized evaporation coils. This problem is magnified in multi-unit buildings because copper tubing may be provided to each unit. This circulation of refrigerant risks exposure of users of the HVAC system to potentially toxic refrigerant because the refrigerant is provided to evaporation coils within each zone to be cooled. The circulation of refrigerant to every zone to be cooled further reduces the overall efficiency of the system since energy is required to move the fluid back-and-forth through the piping from the condenser coils to the localized cooling units (evaporation coils) within the building. Another problem is that each of the localized evaporation coils generate moisture at their particular zone during cooling and said moisture must be taken from the local evaporation coil to outside of the building for disposal. Disposal of the moisture created by these coils usually requires a pump to move the fluid and, as a result, further decreases the overall energy efficiency of the typical HVAC unit.

Several problems also arise with typical ventilating fans in known HVAC systems. One problem is that the venting fans inefficiently circulate air. Office building codes often feature air quality standards that require that a percentage of the inside air be replenished with an outside air over certain designated times. A constant supply of external air from known HVAC systems is not always enough to replace the required amount of air so that additional airflow systems are required to supplement the constant airflows of known HVAC systems. Furthermore, the known ventilating fans of HVAC systems are inefficient because they do not take advantage of cool external air to cool internal air and rely solely on the condensation cycle of refrigerant for temperature control.

SUMMARY OF THE INVENTION

In view of the foregoing, an object of this specification is to disclose an improved variable refrigerant flow (VRF) air conditioning (AC) unit that eliminates the need to run refrigerant lines into the spaces being cooled or heated while providing the benefits and energy savings of a VRF system. It is a further object to disclose a VRF AC system that connects multiple condensate drain pans via one pipe then uses gravity to drain condensation from the condenser coils. It is yet another object of this disclosure to describe a VRF AC system that provides the required minimum outside air as an integral part of the system. Yet another objective of this disclosure is to provide an HVAC system that consolidates fans and refrigerant cycles. Finally, it is an objective of this paper to present a VRF AC system that has an economizer to use outside air to cool inside air if the outside air temperature is lower than the inside air temperature.

In one embodiment, the invention may be a packaged rooftop VRF AC unit that cools and heats multiple zones (or areas/rooms) of a building simultaneously. In a preferred embodiment, the unit is self-contained with flexible geometry to match existing zones of the building (i.e., the unit can be retrofit to existing structures easily).

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other objectives of the disclosure will become apparent to those skilled in the art once the invention has been shown and described. The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached figures in which:

FIG. 1 is a perspective view of a preferred embodiment of the VRF system;

FIG. 2 is a plan view of the preferred embodiment of the VRF system;

FIG. 3 is a side view of the preferred embodiment of the VRF system;

FIG. 4 is an end wall view of the preferred embodiment of the VRF system;

FIG. 5 is an air flow diagram;

FIG. 6 a dimensioned plan view of the preferred embodiment the VRF;

FIG. 7 is a dimensioned side view of the preferred embodiment of the VRF system; and,

FIG. 8 is a dimensioned end wall view of the preferred embodiment of the VRF system.

FIG. 9 a plan view of an alternate embodiment the VRF;

FIG. 10 is a side view of the alternate embodiment of the VRF system;

FIG. 11 is an end wall view of the preferred embodiment of the VRF system;

FIG. 12 is a diagram of the base of the VRF system; and,

FIG. 13 illustrates the installation of the VRF system.

In a typical case, the system may feature the following components with numerals that correspond to the numerals in the figures:

-   (1210) Mitsubishi R2 series fan; -   (1310) an outside air damper; -   (1320) a louver; -   (1340) a filter bank; -   (1341) filter gauge -   (1342) access door -   (1350) an supply air opening; -   (1351) a supply fan and motor assembly; -   (1352) an access door; -   (1360) a return air opening -   (1365) exhaust fan -   (1366) motor assembly. -   (1367) an access door; -   (1368) an access door; -   (1370) exhaust air vent; -   (1371) a backdraft damper; -   (1372) exhaust air louver. -   (1390) expansion coil; -   (1392) a control enclosure; -   (1391) a controller; -   (1393) a drain connection; -   (1394) a removable panel or access door; and, -   (1395) a supply fan (SF) & exhaust fan (EF) variable frequency     drives (VFDs).

It is to be noted, however, that the appended figures illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments that will be appreciated by those reasonably skilled in the relevant arts. Also, figures are not necessarily made to scale but are representative.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Disclosed is as a rooftop HVAC system 1000. FIG. 1 is a perspective view of the preferred embodiment of system 1000. FIG. 2 is a plan view of the preferred embodiment of the system 1000. FIG. 3 is a side view of the preferred embodiment of the system 1000. FIG. 4 is an end wall view of the system 1000. As shown the system comprises: a platform 1100; an external condensing unit 1200; and, a venting box 1300.

Referring to the figures, the external condensing unit suitably features two fans 1210 (e.g., Mitsubishi R2 series fans) that move air over the condenser coils to extract heat from a refrigerant and exhaust the heated air to the ambient heat-sink. Suitably, refrigerant may be cycled to expansion coils 1390 inside the venting box 1300 so that air taken into the venting box 1300 may be conditioned.

As shown, the venting box 1300 suitably features an outside air damper 1310 on both sides of the venting box 1300 (see FIG. 2). Suitably, the damper 1310 may be a valve or plate that stops or regulates the flow of into the venting box 1300. Suitably, the damper 1310 may be used to cut off the flow of air from the outside of the venting box 1300 to the inside of the venting box 1300. In one embodiment, the damper(s) 1310 are 16 W×30 H OSA dampers or actuators. Suitably, the damper(s) 1310 feature louvers 1320 that are slatted downward to admit air into the venting box 1300 while keeping out rain. Suitably, the angle of the slats of the louvers 1320 may be adjustable or fixed. Once inside the venting box 1300, air that has passed through the dampers 1310 into the venting box 1360 may suitably be conditioned as discussed in detail below.

Still referring to FIGS. 2 through 4, the venting box 1300 preferably features a filter bank 1340. Suitably, the filter bank 1340 has a plurality of filters for removing particulates from the air received through the damper 1310. In a preferred embodiment an array of filters are employed to clean the air to appropriate air quality control standards. In one embodiment, a filter gauge 1341 may be employed on the outside of the venting box 1300 so that the filters can be changed according to an appropriate schedule. In a preferred embodiment, the venting box 1300 may feature an access door 1342 so that the filter bank 1340 may be accessed and the associated filters replaced or maintained.

Still referring to FIG. 2, the venting box 1300 suitably features at least one supply air opening 1350 on its floor. In use, the supply air opening 1350 permits conditioned air to exit the venting box 1300 toward the space (not shown) (e.g. a building) to be cooled. In a preferred embodiment, the venting box 1300 suitably features at least one supply air fan and motor assembly 1351 that is positioned inside the venting box 1300 adjacent to the filter bank 1340. In operation, the fan 1351 drives air through the damper 1310, through the filter bank 1340, and toward the supply air opening 1350. Suitably, an access door 1352 is provided to the venting box 1300 so that maintenance may be conducted on the supply air fan and motor assembly 1351. As discussed in detail below, the supply air opening 1350 suitably is divided by ducts into separate air pathways so that multiple spaces may be cooled separately.

FIG. 4 is a rear plan view of the venting box 1300. As shown, the view shows the expansion coil array 1390. Suitably, each expansion coil is independently controlled for conditioning air that passes over the coils 1390. In a preferred embodiment, each coil conditions air for a separate zone of a building (not shown). Suitably, as discussed above, each coil features a damper and ducting so that air conditioning by each coil 1390 may separately be provided through the supply air opening 1350. In a preferred embodiment, driving force for the air is the air supply fan and motor assay 1351. Suitably, the conditioning of the air by the various coils 1390 may suitably be controlled by a controller 1391 (e.g., a Mitsubishi BC controller CMB-P105NU-G) with control components stored in the control enclosure 1392 (e.g., a 36 W×66 H×8 D control enclosure). Although the coils 1390 are programed to condition air at different settings, suitably, each coil 1390 is for each zone being serviced by the cooling units 1390 has its own drain pan and all drain pans associated with each zone are manifolded together to create a single drain 1393 for discharging condensate from the venting box 1300. Suitably, gravity is the driving force for drainage. In a preferred embodiment, each zone does not have its own fan and all rely on the operation of the fan 1351 for movement of air to all zones. Access doors 1394 may be provided so that the coils and cooling units 1390 or controllers 1391 may be accessible inside the venting box 1300. Copper tubing may be provided to the coils from the condenser unit 1200 so that refrigerant may be cycled through the system 1000.

In one embodiment, the system preferably has a system control for the packaged VRF Multi-zone Unit. Suitably, the controller may be capable of controlling individual zones and supply fan air volume and pressure. The zone air volume can be controlled in various ways depending to user preference or local code requirements. In one embodiment, the two main methods are (1) constant volume or (2) variable volume. The constant volume control method involves a scenario where each zone has a “manual fix in position damper.” The damper may suitably be set at a fixed position to deliver a constant amount of air to a space during heating, cooling or ventilation modes. Suitably, the system requires an air balance and supply fan that are also set in a fixed position. The variable volume control method involves a scenario where each zone is equipped with a modulating damper. According to control logic: (A) the damper will go to “full open position” when there is a call for heating or cooling; (B) the damper will go to “minimum position” when a temperature set point has been reached and there is no need for heating or cooling; and, (C) the damper will go to “full closed position” during unoccupied mode. Suitably, the fan controls will involve supply fans (e.g., one or more fans in parallel) that work based on a constant pressure method. Suitably, any time the zone damper changes positon, the supply fans swill adjust to the pre-set pressure point using the variable frequency drive.

As shown in FIGS. 2 through 4, the venting box 1300 suitably features at least one return air opening 1360 on its floor. In use, the return air opening 1360 permits stagnant air from inside the space (not shown) (e.g., a building) to be drawn into the venting box 1300 and exhausted to the ambient via the exhaust vent 1370, which includes a back draft damper 1371 and corresponding louvers 1372. Suitably, the driving force for pulling return air from the inside of the space (not shown) is an exhaust fan 1365 and motor assay 1366 that is positioned adjacent to the return air opening 1360. In a preferred embodiment, the venting box 1300 suitably features access doors 1367 and 1368 so that the damper, 1371, the exhaust fan 1365 and motor 1366 may be properly accessed for maintenance.

FIG. 5 is an air flow diagram for the VRF 1000. Suitably, the outside air dampers 1310 allow fresh outside air into a building to meet code requirements. As shown, the air is filtered by the filter bank 1340. In one embodiment, one or more fans (1351, FIGS. 1 through 4) may be used for delivering the same air to all zones inside of a building, whereby the design can be more than 50% efficient than systems that require one fan per cooling space. In a preferred embodiment, the filter air is provided through a cooling unit or coil (1390), one coil 1390 per zone to be cooled. As shown, each space being serviced by the cooling units 1390 has its own coil in the cooling unit and all drain pans associated with each zone are manifolded together to create a single drain connection from the unit. This consolidation of drain pans is preferably done without mixing air paths for each cooled zone. In one embodiment, the system 1300 has an economizer to use outside air to cool inside air if the outside air temperature is lower than the inside air temperature.

FIG. 6 a dimensioned plan view of the preferred embodiment the VRF. FIG. 7 is a dimensioned side view of the preferred embodiment of the VRF system. FIG. 8 is a dimensioned end wall view of the preferred embodiment of the VRF system. FIG. 9 through 11 are respectively a dimensioned plan view, a dimensioned side view, and a dimensioned end wall view of an alternate embodiment the VRF. In those figures, the system may feature the following components with numerals that correspond to the numerals in the figures:

-   (1) an outside air damper; -   (2) a louver; -   (3) an supply air (SA) opening; -   (4) Mitsubishi R2 series fan; -   (5) a filter bank; -   (6) an access door; -   (7) an access door; -   (8) a filter gauge; -   (9) a supply fan and motor assembly; -   (10) an access door; -   (11) N/A; -   (12) a drain connection; -   (13) a removable panel; -   (14) a control enclosure; -   (15) a coil; -   (16) n/a; -   (17) n/a; -   (18) a controller; -   (19) a single source power panel; -   (20) a SF & exhaust fan (EF) VFDs; -   (21) a backdraft damper with exhaust air (EA) louver; -   (22) walk away grating; -   (23) exhaust fan and motor assembly; -   (24) lifting lugs; p0 (25) N/A -   (26) access door; and, -   (27) access door.

As discussed above, the VRF system suitably features a base 1100. FIG. 12 is a diagram of the base of the VRF system. FIG. 13 illustrates the installation of the VRF system. As shown in those figures, the base 1000 may be suitably installed on a roof curb via a curb mounting that extends from the base 1000.

Although the method and apparatus is described above in terms of various exemplary embodiments and implementations, it should be is understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead might be applied, alone or in various combinations, to one or more of the other embodiments of the disclosed method and apparatus, whether or not such embodiments are described and whether or not such features are presented as being a part of a described embodiment. Thus the breadth and scope of the claimed invention should not be limited by any of the above-described embodiments.

Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open-ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as meaning “including, without limitation” or the like, the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof, the terms “a” or “an” should be read as meaning “at least one,” “one or more,” or the like, and adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that might be available or known now or at any time in the future. Likewise, where this document refers to technologies that would be apparent or known to one of ordinary skill in the art, such technologies encompass those apparent or known to the skilled artisan now or at any time in the future.

The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases might be absent. The use of the term “assembly” does not imply that the components or functionality described or claimed as part of the module are all configured in a common package. Indeed, any or all of the various components of a module, whether control logic or other components, might be combined in a single package or separately maintained and might further be distributed across multiple locations.

Additionally, the various embodiments set forth herein are described in terms of exemplary block diagrams, flow charts and other illustrations. As will become apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternatives might be implemented without confinement to the illustrated examples. For example, block diagrams and their accompanying description should not be construed as mandating a particular architecture or configuration.

All original claims submitted with this specification are incorporated by reference in their entirety as if fully set forth herein. 

I claim:
 1. A variable refrigerant flow heating ventilation and air conditioning apparatus comprising: a platform 1100; an external condensing unit 1200; and, a venting box 1300, said venting box featuring: an outside air damper 1310; a filter bank 1340; a supply air fan and motor assembly 1351; a plurality of cooling units 1390; a supply air opening 1350 that is defined by a plurality of ducting pathways between said plurality of cooling units and a corresponding plurality of zones within a building; a return air opening 1360 that is defined by another plurality of ducting between said plurality of zones within the building and venting box 1300; an exhaust fan and motor assembly; an exhaust vent 1370; wherein said supply air fan and motor assembly 1351 is configured to (a) pull air through the outside air damper, and said filter bank and (b) drive air through said supply air opening along of said ducting path ways to said zone; wherein each of said plurality of cooling units is separately controlled according to a setting that corresponds to the associated zone, said control either being of constant volume or variable volume; wherein said exhaust fan and motor assembly is configured to pull air from said plurality of zones and exhaust said air from the exhaust vent.
 2. The variable refrigerant flow heating ventilation and air conditioning apparatus of claim 1 further comprising a drain defined by the manifolding together of a drain pan from each of said cooling units.
 3. The variable refrigerant flow heating ventilation and air conditioning apparatus of claim 1 wherein drainage of condensate from said cooling units is accomplished by said drain.
 4. The variable refrigerant flow heating ventilation and air conditioning apparatus of claim 3 wherein said drainage flows via the force of gravity.
 5. A method of conditioning air in a building with at least two zones to be cooled comprising the steps of: Locating a venting box and a condenser unit on a rooftop of the building; Wherein said venting box features; an outside air damper to allow ambient air to enter said venting box, a supply air fan, a first evaporation coil; a second evaporation coil; a first ducting pathway from said first evaporation coil to a first one of said two zones to be cooled; a second ducting pathway from said second evaporation coil to a second one of said zones to be cooled; an exhaust air opening, an exhaust fan, and, an exhaust vent; circulating refrigerant between the condensation unit and the evaporation coils; forcing air into the venting box through the outside air damper via said supply air fan; forcing a first portion of the air over the first evaporation coil so that said first portion of said air is conditioned to a first temperature; forcing a second portion of the air over the second evaporation coil so that the second portion of air is conditioned to a second temperature; delivering said first portion of the air to the first one of said zones to be cooled via operation of the supply air fan; delivering said second portion of the air to the second one of said zones to be cooled via operation of the supply air fan; forcing the first and second portions of air through the exhaust opening and the exhaust vent via said exhaust fan.
 6. The method of claim 5 wherein the first evaporation coil has a pan for collecting moisture from the first evaporation coil, wherein the second evaporation coil has a second pan for collecting moisture from the second evaporation coil, and wherein the first pan and second pan are manifolded together into a single drain.
 7. The method of claim 6 further comprising the step of draining moisture from said drain.
 8. A system for conditioning air in a multi-unit building comprising: a rooftop condensation unit; a rooftop venting box comprising a single supply air fan for circulating air and for providing air over a plurality of evaporation coils, wherein each of said plurality of evaporation coils is in fluid communication with a single unit of said multi-unit building; and, a drain that is in fluid communication with all of said plurality of evaporation coils, where said drain operates via the force of gravity to remove moisture from said plurality of evaporation coils. 